From d35673d0f2238874d9d12e85202b21140648ebb0 Mon Sep 17 00:00:00 2001
From: ccamel <camel.christophe@gmail.com>
Date: Thu, 13 Apr 2023 08:53:31 +0200
Subject: [PATCH] feat(logic): add filtered virtual FS

---
 x/logic/fs/filtered_fs.go | 49 +++++++++++++++++++++++++++++++++++++++
 x/logic/fs/virtual_fs.go  |  6 ++---
 2 files changed, 52 insertions(+), 3 deletions(-)
 create mode 100644 x/logic/fs/filtered_fs.go

diff --git a/x/logic/fs/filtered_fs.go b/x/logic/fs/filtered_fs.go
new file mode 100644
index 00000000..1aac4e65
--- /dev/null
+++ b/x/logic/fs/filtered_fs.go
@@ -0,0 +1,49 @@
+package fs
+
+import (
+	"io/fs"
+	"net/url"
+
+	"github.com/okp4/okp4d/x/logic/util"
+)
+
+// FilteredFS is a wrapper around a fs.FS that filters out files that are not allowed to be read.
+// This is used to prevent the interpreter from reading files, using protocols that are not allowed to be used
+// by the interpreter on the blockchain.
+// The whitelist and blacklist are mutually exclusive. If both are set, the blacklist will be ignored.
+type FilteredFS struct {
+	decorated fs.FS
+	whitelist []*url.URL
+	blacklist []*url.URL
+}
+
+var _ fs.FS = (*FilteredFS)(nil)
+
+// NewFilteredFS returns a new FilteredFS object that will filter out files that are not allowed to be read
+// according to the whitelist and blacklist parameters.
+func NewFilteredFS(whitelist, blacklist []*url.URL, decorated fs.FS) *FilteredFS {
+	return &FilteredFS{
+		decorated: decorated,
+		whitelist: whitelist,
+		blacklist: blacklist,
+	}
+}
+
+// Open opens the named file.
+// The name parameter is a URL that will be parsed and checked against the whitelist and blacklist configured.
+func (f *FilteredFS) Open(name string) (fs.File, error) {
+	urlFile, err := url.Parse(name)
+	if err != nil {
+		return nil, err
+	}
+
+	if !util.WhitelistBlacklistMatches(f.whitelist, f.blacklist, util.UrlMatches)(urlFile) {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrPermission,
+		}
+	}
+
+	return f.decorated.Open(name)
+}
diff --git a/x/logic/fs/virtual_fs.go b/x/logic/fs/virtual_fs.go
index 9529e6ab..dba6a235 100644
--- a/x/logic/fs/virtual_fs.go
+++ b/x/logic/fs/virtual_fs.go
@@ -16,12 +16,12 @@ var _ fs.FS = (*VirtualFS)(nil)
 
 // NewVirtualFS return a new VirtualFS object that will handle all virtual file on the interpreter.
 // File can be provided from different sources like CosmWasm cw-storage smart contract.
-func NewVirtualFS(ctx goctx.Context, handlers []URIHandler) VirtualFS {
+func NewVirtualFS(ctx goctx.Context, handlers []URIHandler) *VirtualFS {
 	router := NewRouter()
 	for _, handler := range handlers {
 		router.RegisterHandler(handler)
 	}
-	return VirtualFS{
+	return &VirtualFS{
 		ctx:    ctx,
 		router: router,
 	}
@@ -36,7 +36,7 @@ func NewVirtualFS(ctx goctx.Context, handlers []URIHandler) VirtualFS {
 // Open should reject attempts to open names that do not satisfy
 // ValidPath(name), returning a *PathError with Err set to
 // ErrInvalid or ErrNotExist.
-func (f VirtualFS) Open(name string) (fs.File, error) {
+func (f *VirtualFS) Open(name string) (fs.File, error) {
 	data, err := f.router.Open(f.ctx, name)
 	if err != nil {
 		return nil, &fs.PathError{